Will the Internet spoil ‘Downton Abbey’?

LOS ANGELES — There are many delicious reasons to watch the returning “Downton Abbey” and an exasperating one to skip it: The cover’s been blown on major plot twists.

In what may be outsized revenge for the American Revolution — or payback for years of exporting lousy U.S. TV and fast food — the Brits are sharing “Downton Abbey” with us, but only after first airing each season.

That wouldn’t matter much in the drama’s early 20th-century setting but we’re not there, are we, PBS and U.K. network ITV? A little gimmick called the Internet makes it impossible to keep story developments from spreading like germ warfare.

As with sports fans who must avoid all media and big-mouthed friends to keep game scores a surprise, “Downton Abbey” addicts are forced to shun rude news reports and blogs about what happens to character A, B or C (no spoilers here, promise).

Heedlessly type in “Downton Abbey season three” online and you risk stumbling into the startling truth that … well, never mind. If you know, you have our sympathy. If you don’t, live in blessed ignorance and careful isolation from Sunday’s debut until the Feb. 17 season finale.

“It is unfair that England gets to see ‘Downton Abbey’ before us because we beat them in a war” was the saucy comment posted on Twitter by producer Damon Lindelof of “Lost” fame.

It’s certainly a development galling enough to draw insults. But as Downton’s courtly master, Lord Grantham (Hugh Bonneville), once rebuked a blunt-spoken visitor: Steady on, sir, the ladies have suffered quite enough of a shock!

Rebecca Eaton, executive producer of PBS’ “Masterpiece” showcase that’s home to “Downton,” contends it’s premature to assess the impact here of the U.K. airing that wrapped Christmas Day. Will ratings be dented by dampened enthusiasm or piracy?

“It will be difficult to say until it airs in this country,” Eaton said, with the size of the audience providing a key measurement.

The bar is high compared with last year, when “Downton Abbey” became the most-watched series ever for “Masterpiece” with more than 17 million viewers across seven episodes. With its swooning, buzz-worthy romances, the drama also fed social media and gave PBS a new veneer of cool.

But what’s to be done if the season endgame is stuck in your brain? As a famous Brit said in more dire circumstances, never surrender! Go along for the ride that the beautifully produced soap opera-cum-fairy tale offers, admiring how the devilishly clever Julian Fellowes, its creator and writer, foreshadows the events to come.

As Downton’s residents adjust to post-War War I England, “there are chills and spills involved in that for all the characters, some laughs and some tears,” as Fellowes neatly summed it up.

Knowing the destination doesn’t mean you can’t appreciate the scenery, including these highlights:

— Michelle Dockery keeping it real as Lady Mary, who’s surrendered to love with Matthew (Dan Stevens) while barely softening her sharp edges and steely devotion to family tradition. Bonus: The willowy actress was born to wear sleek 1920s dresses.

— Fashion and its evolution, as Downton’s upstairs ladies move from lovely but fussy wardrobes to sassier, clean-lined garb and (except for steadfast Mary) shorter hair, reflections of liberating changes that include the promise of universal suffrage for all British women.

— Stevens as golden-boy Matthew, emerging intact from World War I and still conflicted about his future role as lord of the manor. A side game: See if Stevens, smart as he is, looks distracted by the novels he read on the set as a judge for Britain’s Man Booker Prize.

— Cultural, medical and other period tidbits, which are fascinating and a reminder that wise historians never would choose to live in a time before their own. In one instance, a character who may have cancer is told that test results will take up to two nerve-shattering months.

— Fellows’ charming faith in the tender side of revolutionaries, at least ones that mate with landed gentry. Irish chauffeur-turned-activist Tom Branson (Allen Leech), who previously turned moist-eyed over the murder of the Russian royal family, loses it again in season three over fiery political warfare.

— A stately house, but fast-paced action. Fellowes said he took a cue from the American mash-up approach to storytelling perfected in shows like “ER” and “The West Wing,” with stories big and small, sad and funny and “all sort of plotted up together.” The look is period but the energy is “much more modern,” as Fellowes put it.

But modernity can be troublesome, proof being the Internet imperiling the drama’s surprises for U.S. viewers. Whatever the outcome, Eaton said “Masterpiece” will tread carefully in making changes.

ITV is the primary funder of “Downton Abbey” and has international premiere rights. While a September debut fits the U.K. TV marketplace, it would mean stiffer competition for “Downton” as U.S. networks launch their fall slates, Eaton said.

“We want to make sure we don’t do something with ‘Downton’ that will hurt it in the long run,” she said — which, for now, extends to the drama’s fourth season set to air on “Masterpiece,” its co-producer with Carnival Films.

As for the current run, Eaton, who’s no spoilsport, had only this to say: “I think it’s the best season yet.”